Bonsai

Bonsai Biotherapeutics is a Swedish biotechnology company specializing in the development of antigen-specific tolerance-inducing biologics for the treatment of rare autoimmune diseases. Formed in 2025 through the merger of Toleranzia AB into Flerie AB, the company utilizes a proprietary platform to create "tolerogens" that restore the immune system's normal tolerance to self-antigens. Its lead candidate, TOL2, is a recombinant protein currently in Phase 1/2 clinical development for the treatment of generalized myasthenia gravis, specifically targeting the acetylcholine receptor-mediated immune attack. The company is also advancing TOL3 for ANCA-associated vasculitis and exploring other orphan autoimmune indications. Headquartered in Gothenburg, Bonsai Biotherapeutics aims to provide disease-modifying, potentially curative therapies that address the underlying cause of autoimmune dysfunction rather than merely managing symptoms.